Rial Juan wrote: > On Mar 29 Joseph S. Gardner wrote: > > > From what I can find a CRC error is Cyclic Redunancy Check but I have no > > clue what it means or what caused it. I can tell you that the machine > > has been up and running almost flawlessly 24/7 since October. > > I once knew the details about this, but I already took that exam last year, so I > already forgot ;) > > Anyway, it sorta boils down to this: since harddrives can write erroneous data > (a glitch in the circuits can cause this) it's best not only to write the > information you need to the disk, but also some extra info that can help you > determine if the data on disk is error free. For example a parity bit, that is > set to 1 if there's an odd number of 1's in the preceding byte, or to 0 if > there's an even number of 1's. > > Of course, a parity bit only helps you detect an error, and it doesn't even do a > pretty good job at it. So they invented more sophisticated ways of telling if a > byte was written right or wrong. But that only helpt them to determine the wrong > bytes; it offered only error-check; not error-correction. So they pondered > somewhat further along the road, and finally came up with something that would > help them detect errors, and in most cases even correct them. The CRC-check is > one such algorithm. > > The CRC-error you got could be caused by shutting down the computer while it was > writing data to disk, or it could be caused due to the computer hanging while it > was writing to disk. Just imagine what would happen if it's writing to disk, and > halfway there it suddenly hangs... Especially since linux doesn't write to disk > rightaway, but buffers write-data in memory to flush it to disk every once in a > while. > > Anyway, due to the way in which Linux is written, it is impossible for a regular > application to "hang" the PC. Explaining this would require too much space, but > if you're interrested in the matter, I suggest you pick up a copy of "Operating > System concepts" by Abraham Silberschatz and Peter Baer Galvin (Addison-Wesley) > from the library. > > It might appear as if the system is hanging, eg because it's in an infinite > loop, and too busy to respond to anything... But in theory it shouldn't have > crashed. But then again; my box often crashed a while back too, when I was in X. > I also believed it was X that was causing all this trouble, which in theory was > impossible; in the end as a kinda last-resort solution I had my ethernet card > and sound card trade places, and problem solved. Now it runs for days in X > without crashing once. It would run weeks or ever years, but I sometimes like to > reboot to W95 for some serious gaming ;) > > -- > > Rial Juan <http://nighty.ulyssis.org> > e-mail: [EMAIL PROTECTED] > Thanks Rial, The curious thing is that the thing has run great for so long until I installed 7.0-2 to get some new features I wanted. The disk cache makes a lot of sense except that the machine was left in this "hung" mode for several hours last night until I got home to check it out. I wonder if it is possible that something might be interupting the disk write (several people have sugested Java in Netscape) Things to ponder Thanks -- Joseph S. Gardner Senior Designer / Technical Support Kirby Co., Cleveland, OH [EMAIL PROTECTED] Linux is like a wigwam... No windows, no gates. Apache inside Registered linux user #1696600 ICQ #63389227
